The phonon dispersion and line-width in a single crystal were measure along the Γ-A, Γ-M, and A-L directions, using inelastic X-ray scattering. Density functional theory was used to compute the effect of electron-phonon coupling and anharmonicity upon the line-width; thus obtaining excellent agreement with experiment. Anomalous broadening of the Egg phonon mode was found all along Γ-A. The dominant contribution to the line-width was always the electron-phonon coupling.

Phonon Dispersion and Lifetimes in MgB2. A.Shukla, M.Calandra, M.D’Astuto, M.Lazzeri, F.Mauri, C.Bellin, M.Krisch, J.Karpinski, S.M.Kazakov, J.Jun, D.Daghero, K.Parlinski: Physical Review Letters, 2003, 90[9], 095506 (3pp)